In an absolute powerfest in the feature night match, Cibulkova and Williams went toe-to-toe under the lights, with Cibulkova coming out far stronger - she went up a set and a break, 61 10 - but Williams fighting back to take the second set, 7-5, though she did have a set point a few games earlier at 5-3.

Things were streaky in the third set - Cibulkova stormed out to a 4-1 lead, then Williams cut that lead down to 4-3 and had points for 4-all. But the last push went the No.10-seeded Cibulkova's way, as she closed the No.29-seeded Williams out with that aforementioned forehand winner, 61 57 63.

Cibulkova, who is currently at a career-high ranking of No.11, is one win away from breaking the Top 10 for the first time - if she wins her quarterfinal match on Wednesday she'll break the elite.

Standing in her way of that honor - and the semifinals - is No.3 seed Radwanska, who battled two hours and 33 minutes earlier in the day to make it past Ukrainian teenager Elina Svitolina, 76(5) 57 62.

"It was really tricky because I didn't know her and she played really solid tennis in all three sets," Radwanska said. "She's a great player and had a really good run here - a couple of very good wins.

"I think she's really playing some very good tennis these days."

After getting broken when serving to stay in the second set at 5-6 - and obviously dropping the set there - Radwanska had an uncharacteristic display of anger with her racquet. But after the match, the always-bubbly fan favorite showed her funny side, an impressive ability to block the incident out.

"That's the first time I'm hearing about that!" she joked when asked about it.